Retractor blades and rakes are mounted to a positioning apparatus including a supporting framework positioned adjacent to the subject undergoing surgery. Types and sizes of blades and rakes used in an operation, and during different stages of one operation, can depend upon a number of factors, including but not limited to, the type of the operation, the particular part of the anatomy operated on, the body weight of the individual operated on, and so forth. It is convenient to be able to change the specific blades and rakes mounted to the positioning apparatus during the course of the operation. At the same time, the positioning apparatus for the retractor blades and rakes should present minimum obstruction to the surgical team's activities, particularly in the area of an incision.
Interchangeable retractor blades are known and have been used in surgery for a number of years. Interchangeable blades, of various lengths, have been applied to abdominal surgery where the body walls of patients vary substantially in thickness. However, in certain retraction systems, the blades and rakes are fixed to the ends of elongated shafts, which are in turn mounted to the support frame. Elongated shafts afford the possibility of locating the supporting framework of the positioning apparatus well clear of the incision. In retractor systems incorporating blades disposed at the ends of shafts and flexible arms, the shafts/arms and blades have been of one-piece construction, and a change of a blade or rake has involved removal of a shaft/arm and replacement with another shaft/arm carrying the desired blade or rake. Where the shaft is of a high precision, threaded type, maintaining an inventory of appropriately sized blades is expensive. However, no suitable technique of replaceable attachment of blades to shafts, affording quick replacement of blades, has been available.